Looks like we have to test for internal functions unfortunately
since the public V8 snapshot API is available no matter whether
the library really supports it or not.
Splits longish v8js.cc file into pieces. It used to contain the
definitions of all V8Js exception classes, the V8Js class itself as
well as the V8Object/V8Function classes... besides the module setup
code itself.
This change factors out all exception class definitions into a
seperate pair of files (v8js_exceptions.*).
The V8Js class definition itself is moved to v8js_class.* pair,
with the v8 init & call code moved to v8js_v8.* pair
and the watchdog timer to v8js_timer.* pair.
The V8Object/V8Function code was moved to v8js_v8object_class.*
pair, not differentiating between the two like before.
